air help
 

what could cause complete lack of air in the cabin of a 1987 420sel?

i changed the monovalve and even the old one looked decent....right now have some defrost and coming out of all vents i believe

but i need some help so opinions please

thank you

lyle in austin

Lots of things can can cause poor output of air. The blower motor bearings can get dry and stiff dragging the blower speed down considerably. The blower regulator can go bad not putting the juice to the blower motor. The pushbutton can get iffy not telling the regulator how much juice to put out. The vacuum system can have all sorts of problems too causing the airflow to not go where it's supposed to, giving the impression of poor blower output. What I'm getting at is that it will require a competent diagnosis to fix properly. There is no replace "x" because that is what usually goes bad. Start by checking the fuses, then check the voltage at the blower motor. Depending on what is found there will determine the course of further repair or diagnosis.

Taking the year and model into consideration, I would suspect the vacuum actuators. Couple of them are easy to get to, a couple of them, not. You will want to check behind your glovebox....there are a couple of them there. Hope you have small hands.